Electric clock.



w. H. THOMPSON.

ELECTRIO OLOGK.

APPLICATION FILED APR. 1, 1912.

, Patented Apr. 29, 1913.

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W. H. THOMPSON.

ELECTRIC CLOCK. APPLICATION nun APR. 1, 1912.

Ptefitd Apr. 29, 1913. 1

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speciloation ofietterrl'atent Patented Apr. 29 V3. Application filed April 1, 1912. Serial as. 687,980.

To a ll'whon it m'ay cor tcern I Be it known that-I, WILLIAM HnmmasoN THOMPSON, a citizen 'of the United States,

- residing at Memphis, "in' the county of Shelb vente certain new and usefulyIm rovements in Electric Clocks; 'andI do ereby declare the following to be a full, clear,

'and exact descriptioufof the invention, such.

as will enable othersj skilled in the art to which it appertains to make and use the same. 3 1

My' invention relates to improvements in electric clocks, and it consists in the constructions, combinations and arrangements herein described and claimed.

An object of my invention is to provide an improved electric clock, in which a uni- -form driving force will be exerted on the clock train with an entire freedom from .binding and, frictional strains under all practical conditions of continuous-operation.

A further object of my invention is to rovide an improved electric clock having shiftable electrical contacts adapted to make and break contact at different points on their engaging surfaces, thereby. minimizing danger of'deterioration of the engaging sur- .faces by sparking.

A further-object of my invention is to provide an improved electric clock, in which contact surfaces under conditions of long coiiperating electrical contacts for the con-. trolling current are carried, respectively, by

a gravity-actuated driving mechanism and an independently movable electrically-actuated means, for engagement wit-h acombined rolling and sliding contact, thereby insuring the maintenance of effectively clean 1; Fig. 3 is a perspective View of the reciprocatingly-mounted rack constituting my free, gravity-actuated driving member; Fig. 4 is a detail view of the balanced gearwheel and spring-retaining mechanism rotatably mounted on the center post for.transmitting a uniform driving force from the gravityand .State of Tennessee, have in-' placement. of the rack Referring to the drawings a gear wheel actuated rack; F 5 is an axial section of I the parts shown in Fig. 4; and Fig. 6 is a 1 and a spring-retainingmechanism 2 are rotatably mounted on the center post 3 .of

any well known clock train, and operatively connected by a spring-pressed pawl 1 and ratchet teeth 5. carried by the, respective arts; reverse movement of said mamtainmg mechanism being prevented bya gravityactuated pawl 6 pivoted at 7 to the clock frame in engagement with said .ratchet.

teeth 5.

A vertical rack 8'is reciprocatingly mounted in guides 9 and. 10 on the clock-frame in mesh with the ea'r'wheel 1; the upper. portion of said ra k ;member comprising a rod 11 sliding in the guide 10 to prevent. any danger ofbindingthrough an lar "disconst-itutes a free, gravlty-actuated member tangentially engaging the gear 1 to transmit guides.- he rack 8' a uniform driving force through the latter under'all practical conditions.

a A lever 12 is fulcrur'ned at 13 and carries at its opposite ends the armature 14 of an 'electro-magnet 15 and an insulated contact plate 16 for engagement by a contact "pin 17 on the gear wheel 1;' said gear wheel being provided with a weighted portion 18 for accurately counter-balancing the pin 17 and pawl t carried thereby. A flat spring" 19 on the lever is yieldingly maintained in engagement with a fixed stop 20 by a single leaf spring- 21 of "non magnetic material carried by the. armature 14 in engagement with the magnetic' core 22; the swlng of said lever 12 being limited by a rigid arm 23 carried thereby for engagingsaid stop 20. y

The electro-magnet 15 is shown in an electric circuit having its respective'terminals connected to the clock train and to the insulated contact plate 16. i

In the operation of, my invention, the

gradual descentof the. rack 8 under the action of gravityv transmits a uniform force through the gear wheel 1 to the clock train; the constant product of the weight of said rack and the radius of said .wheel transmitting a uniform torque through the maintaining mechanism 2 to the center post 3.

As the wheel 1 is thus rotated by the weight of said rack, the contact pin 17 engages the contact plate 16 and the magnet is ener- @2931 to sharply attract the armature 14 und 'swingthe lever" 12' about its fulcrum. This movement of the lever 12 causesthe contact plate 16 to suddenly elevate'or kick -up, the pin" engaged thereby, and thu rotate-thewheel1-toraisethe rack 8.

The'velo'city imparted tothe rack causes the latter to move upwardly beyond the position to which it iselevated by the engage-v ment ,of the contact plate 16 with the pin 1-7, andthereby .irotates the wheel '1 sufiiciently tofraise said pin' '17 from the plate and break the eontacttherehetween, see Fig. 1; During;

this sudden elevation f the, rack 8',- the spring maintaining mechanismmaintains a uni-forn gdrivingforceon the center post 3, and lnsures an accurate and regular operafervent points, they engage .witha combined .l i' Ollingf and slidingqcontact which has. a

- scouringp-eflect tending to maintain etfi- .54.1

ciently clean. contact surfaces thereon; this scouring action being progressively aug merited; after the; initial 7 engagement 4 of said contacts -'by="-the' gradually increased resist? ance oft-he spring 19 otonthe' downwardmovement ofthe contact plate 1 6. i This im-i;

' p'rovedconstruction' enables the contacts to beadvantageously vformed of silver, or other IIIGtILlzOfhlgh conductivity, and avoids the irregularities. due to the residual magnetism. and other defectsrinherent in the platinum" contacts-of previous constructions. I It will be noted that the impulse of the contact plate 16 is exerted on the pin 17 at a point intermediate of the center post 3 and rack 8,: thereby eliminating all danger of wear and-irregular running by bindingor frictional strains.

I have illustrated and described preferred and satisfactoryconstructions, but changes could b'e-madewithin the spirit'and scope of my-inventionfiil l V v n s a In an'electric clock, the combina j l; the contacts-l6 and17 rotate'about'di'f 1,0eo,eso

p I claim': v I 1. In an electric clock, the combination of a wheel mounted on the center post for transmitting power to the clock train, a free, gravity-actuated member engaging said wheel, and electrically-actuatedmeans for actuatingly "e igaging said wheel at a point intermediate of said center post and gravityactuatedvmember.

2. Inan electric clock, the combination of a gear wheel mounted on the center post for transmitting power-to the clock train, a. free rack reciprocatingly mounted in mesh with said gear, electrically-actuated means for termedia-te of said rack and centerpost, and electrical contacts on said transmitting and I electrically-actuated means .for controlling 1 the opera-tionof the latter. v

tion of a gear wheel rotatably mounted on the cen-' ter post, retaining mechanism connecting said gear-to theflclock train, a free rack re- "ciproseati'ngly mounted in meshwithsaidtuatingly engaging said gear ata point in termediate of said rack and center post. 1

4. In an electric clock, the combination of gravity-actuated driving mechanism for the clock train, electrically-actuated means for "storing energy in said driving mechanism al electrical circuit for controlling said means, cooperatingelectrical contacts in said circuit carried by said driving mechanism and electrically-actuated means for engage- -ment with a combined rolling and slidingaction, and'means for progressively increasing the-engaging pressure of said contacts of the latter".

In testimony whereof, I afiix my signature, 'in presence of two witnesses,

' 7 WILLIAM HENDERSON THOMPSON. Witnesses: HE RY" CROFT,

Tnos. M. Seances;

I s I actuatingly engaging sald gear at a pOlllbiIl 'gear, and electrically-actuated means for ac- 1 during such sliding and rolling-engagement 35 

